1. Field of the Invention
The present invention pertains to automatic washing machines and, more particularly, to a drive system for use in an automatic washing machine.
2. Description of the Prior Art
It is widely known in the art of automatic washing machines to provide a drive system for producing both spin and agitation in a cycle of operation. During a typical spin portion of the cycle, a washing machine basket, containing a generally unevenly distributed load of wet clothes, is rotated at a high rate of speed. This rotation develops centrifugal forces resulting in a certain degree of drying of the clothes. Rotation of the washing machine basket can be accompanied by a considerable amount of vibration, not only of the clothes basket itself but also the entire automatic washing machine, if the rotating elements are not properly counterbalanced. Many systems have been employed for the purpose of reducing vibration of the washing machine basket and/or preventing the vibration from being transmitted to the supporting structure. Commercial washing machines can be readily constructed of heavy parts to overcome any uneven load distribution in the washing machine basket so as to minimize or prevent any vibration of the machine as a whole. The inclusion of heavy supporting parts for a domestic machine is objectionable since machines must be readily transportable and are generally of standard sizes.
A typical spin portion of a cycle of operation is effected by rotating the clothes basket by means of a motor driven transmission assembly so that during the spin, the transmission assembly is also rotated at a high rate of speed. The transmission assembly is rather heavy as compared to the washing machine basket itself and therefore can considerably affect the balancing of the washing machine during spin. Therefore, it is extremely important to the overall vibration dampening of the washing machine during operation to properly counterbalance the transmission assembly during spin. Unfortunately, such transmission assemblies generally include a plurality of interengaged transmission elements that vary in position during operation of the washing machine. Due to the considerable weight of each of these elements, their respective positions during any given spin cycle can greatly affect machine balancing.
It has heretobefore been known to maintain the plurality of elements of an automatic washing machine transmission assembly fixed relative to each other during spin while rotating the transmission assembly as a whole. In such known systems, the transmission elements have been braked at random locations and a balancing counterweight has been provided for the transmission assembly to minimize vibrations. According to such systems, the counterweight is sized and positioned for the average balancing location of the transmission assembly. Obviously, since the transmission elements in such an arrangement are randomly stopped, the counterweight cannot be accurately positioned throughout each spin.
Therefore, there exists a need in the art for a drive system for producing spin and agitation in a cycle of operation in an automatic washing machine wherein a transmission assembly of the drive system is accurately counterweighted so as to be properly balanced during spin in order to minimize developed vibrations.